Nitrogen disulfide

NSS, SNS (nitrogen disulfide), SSNS, O2SOSO (sulfur dioxide dimer), He C6o... 

The shape of a large protein is influenced by many factors including of course Its primary and secondary structure The disulfide bond shown m Figure 27 18 links Cys 138 of carboxypeptidase A to Cys 161 and contributes to the tertiary structure Car boxypeptidase A contains a Zn " ion which is essential to the catalytic activity of the enzyme and its presence influences the tertiary structure The Zn ion lies near the cen ter of the enzyme where it is coordinated to the imidazole nitrogens of two histidine residues (His 69 His 196) and to the carboxylate side chain of Glu 72... 

Chemical Properties The formation of salts with acids is the most characteristic reaction of amines. Since the amines are soluble in organic solvents and the salts are usually not soluble, acidic products can be conveniendy separated by the reaction with an amine, the unshared electron pair on the amine nitrogen acting as proton acceptor. Amines are good nucleophiles reactions of amines at the nitrogen atom have as a first step the formation of a bond with the unshared electron pair of nitrogen, eg, reactions with acid anhydrides, haUdes, and esters, with carbon dioxide or carbon disulfide, and with isocyanic or isothiocyanic acid derivatives. 

The reactive species that iaitiate free-radical oxidatioa are preseat ia trace amouats. Exteasive studies (11) of the autoxidatioa mechanism have clearly estabUshed that the most reactive materials are thiols and disulfides, heterocycHc nitrogen compounds, diolefins, furans, and certain aromatic-olefin compounds. Because free-radical formation is accelerated by metal ions of copper, cobalt, and even iron (12), the presence of metals further compHcates the control of oxidation. It is difficult to avoid some metals, particularly iron, ia fuel systems. 

Sodium a2idodithiocarbonate decomposes with evolution of nitrogen gas on addition of iodine, thus providing a useful quaHtative test for the presence of residual carbon disulfide ia aqueous solutions (25). 

The 27T-electrons of the carbon-nitrogen double bond of 1-azirines can participate in thermal symmetry-allowed [4 + 2] cycloadditions with a variety of substrates such as cyclo-pentadienones, isobenzofurans, triazines and tetrazines 71AHC(13)45). Cycloadditions also occur with heterocumulenes such as ketenes, ketenimines, isocyanates and carbon disulfide. It is also possible for the 27r-electrons of 1-azirines to participate in ene reactions 73HCA1351). 

Diphenyl disulfide (phenyl disulfide) [882-33-7] M 218.3, m 60.5 . Crystd from MeOH. [Alberti et al. J Am Chem Soc 108 3024 1986]. Crystd repeatedly from hot diethyl ether, then vac dried at 30° over P2O5, fused under nitrogen and re-dried, the whole procedure being repeated, with a final drying under vac for 24h. Also recrystd from hexane/EtOH soln. [Burkey and Griller 7 Am Chem Soc 107 246 1985.]... 

There is no apparent reaction between the disulfide and dilute acids at room temperature, but with more concentrated acids liberation of nitrogen takes place and the solution becomes turbid due to the formation of sulfur. 

The disulfide has a special interest as the catalyst in the carbon disulfide-catalyzed iodine-azide reaction. No perceptible nitrogen evolution will take place in a solution containing iodine and azide ions without the presence of a catalyst. Thiosulfates, sulfides, and many other sulfur compounds act as catalysts. In 1922 Browne et found that carbon disulfide is a powerful catalyst in this... 

A different reaction takes place between an ethereal solution of the disulfide and hydrogen azide this reaction proceeds according to Eq. (15). Probably the principal step of this reaction is the spontaneous decomposition of the disulfide into nitrogen, sulfur, and... 

Pyridinium ylide is considered to be the adduct car-bene to the lone pair of nitrogen in pyridine. The validity of this assumption was confirmed by Tozume et al. [12J. They obtained pyridinium bis-(methoxycarbonyl) meth-ylide by the photolysis of dimethyl diazomalonate in pyridine. Matsuyama et al. [13] reported that the pyridinium ylide was produced quantitatively by the transylidalion of sulfonium ylide with pyridine in the presence of some sulfides. However, in their method it was not easy to separate the end products. Kondo and his coworkers [14] noticed that this disadvantage was overcome by the use of carbon disulfide as a catalyst. Therefore, they used this reaction to prepare poly[4-vinylpyridinium bis-(methoxycarbonyl) methylide (Scheme 12) by stirring a solution of poly(4-vinylpyridine), methylphenylsulfo-nium bis-(methoxycarbonyl)methylide, and carbon disulfide in chloroform for 2 days at room temperature. 

Write the formulas for the following compounds and give the weight of one mole of each carbon disulfide, sulfur hexafluoride, nitrogen trichloride, osmium tetroxide. 

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